Monday, December 28, 2009

I've been visiting family out of town - we got here just in time to be snowed-in for Christmas. So I thought some wintry chemistry would be appropriate.

Slashdot recently had a listing about a new anti-freeze molecule that has recently been found in the Alaskan beetle, Upis ceramboides. Anti-freeze molecules have been observed in a variety of plants and animals that help them resist damage from the formation of ice crystals in their tissues. All previous anti-freeze molecules have been proteins, but this new one is a sugar. It may also have a lipid component, but that isn't clear.

The sugar, xylomannan, is a polymer of mannose and xylose. Originally the researchers assumed that the anti-freeze compound in their beetles was a protein, like other known anti-freeze compounds. However they couldn't visualize it with electrophoresis, and the UV-vis and NMR spectra didn't show any sign of peptide bonds or aromatic sidechains like tyrosine or phenylalanine. Instead, the NMR was consistent with a sugar molecule, which was confirmed by GC/MS.